What is the characteristic result of adding blue Fehling's solution to an aldehyde?

When blue Fehling's solution is added to an aldehyde, a characteristic reaction occurs that results in the formation of a brick red precipitate. This reaction is based on the reduction of the copper(II) ions present in the Fehling's solution, which is typically in the form of a blue copper(II) tartrate complex.

Aldehydes are known as reducing agents; they have the ability to reduce copper(II) ions to copper(I) oxide. When the aldehyde is introduced into the solution, it donates electrons to reduce the copper, leading to the transformation of the blue solution into a red precipitate of copper(I) oxide. This change indicates a successful reaction between the aldehyde and Fehling's solution, and it is a common test used to identify the presence of aldehydes in organic compounds.

In contrast, the other potential outcomes do not represent the behavior of aldehydes with Fehling's solution. The presence of a yellow precipitate or a green solution does not occur in this reaction. A blue solution would indicate that no reaction has taken place, which is not the case when an aldehyde is introduced. Thus, the formation of a brick red precipitate serves as